Sizing Boolit and Expanding Neck for 308W

[edctexas]

I am new to cast in rifles. I have taken a chamber cast and know how to correctly arrive at the true dimensions. The true bore is 0.3005 and the true groove is 0.3085 (measured with Mitutoyo digital calipers on the casting). What should be the right diameter to use for sizing the boolit. I am starting with boolits dropping at 0.3100.

What size expander should I be using to load the boolit into the case? The chamber over the neck is 0.3456. In front of the case edge, there is what I would call a freebore that is 0.268 in long. This is 0.3095 dia. This dimension tapers into the groove and land at that 0.268 inches from where the case neck has to stop.

I need to buy a Lee push thru sizer and a new method of expanding the case neck to have some neck tension on the sized boolit. Any help would be appreciated.

Ed C

[bhn22]

Since your throat is at .3095, I'd size to .310. Try seating a bullet in an empty case and chambering it in the rifle. If it chambers and unchambers freely, .310 would be my preferred starting point. For neck expanding, I use Lyman M dies. They expand the necks, and allow you to flare the case mouth as much, or as little as you desire. I'm assuming you're using a bore riding bullet design, so also make certain your bullet noses enter the rifling with only light engraving at the most, so around .300 is where I'd want the bullet noses to be. You're likely to get a lot of differing opinions on some of this.

[popper]

310, M die (or equal - someone here is making them now), flare with the Lee universal tool. You didn't state the boolit you want to use, GC & >15 BHN. They tend to like 160-180 gr.

[RayinNH]

Ed if your boolits are coming out at .310, start there, no sizing required. As mentioned the Lyman M die or the Lee universal die is used to flare case mouths/neck. On the cheap you can use a pair of needle nose pliers to flare the case.

I size to .311 and expand the case to .310. I load singly into the bolt action and use no crimp. I'm in no hurry :smile:.

[cbrick]

The Lyman M die will both expand the necks and bell the case mouths. I have & use many different M dies but I prefer the RCBS style and use them in the sizes that I have them. Your expanded necks should be .0015" to .002" smaller than sized diameter for neck tension. Get the LEE .310" sizer and size them very little to not at all, load them up and shoot them. At the worst you should be pretty close.

Rick

[Jupiter7]

NOE is making replacement expanders for the LEE Universal expanding die that turn it into a true stepped expander like the lyman. I have used both, both work as they should.

[Jupiter7]

The Lyman M die will both expand the necks and bell the case mouths. I have & use many different M dies but I prefer the RCBS style and use them in the sizes that I have them. Your expanded necks should be .0015" to .002" smaller than sized diameter for neck tension. Get the LEE .310" sizer and size them very little to not at all, load them up and shoot them. At the worst you should be pretty close.

Rick

If only Lee would make a .310 sizing die!! I honed a .309, but found .311 works for most my .30's well.

[jmort]

you can get any size you want, up to. 575"
it cost $35. Look in the custom section for custom sizers

[geargnasher]

Read post #2 here, it applies to pretty much all rifle bullet fitment and is one of the best descriptions that has been written here: http://castboolits.gunloads.com/showthread.php?267981-Loading-303-with-Black-Powder-Will-it-Work&p=3120668#post3120668

Generally, using a bushing type neck sizing die with a full-length body sizer will let you size down the necks the proper amount for your rifle without over-doing it like standard, FL dies do. Work the necks as little as possible. Use a TRUE expander such as CBRICK mentioned (either will work, I much prefer RCBS myself) and select a spud that is about .001-2" smaller than your chosen bullet sized diameter. I'd get a .309 die myself, the bullet may expand up to exactly throat entrance size (.3095") depending on how tough your alloy is and how soon after casting you size them. If you get a .310 die it might be a touch too big, depending on bullet shape and how it fits the throat, which could cause seating depth issues if the front band is too large to squeeze up into the rifle throat's freebore.

.0015-.0020" interference fit between neck and bullet works the best for me in all my rifles, giving sufficient tension for self-loading rifles even without a crimp.

Gear